The present invention relates to a new class of metallocenes, to a catalyst for the polymerization of olefins comprising said metallocenes and to a processes for the polymerization of olefins carried out in the presence of said catalyst. The invention also relates to a novel class of ligands useful as intermediates in the synthesis of said metallocenes.
Many metallocene compounds known in the state of the art are active as catalyst components in olefin polymerization reactions, in association with suitable cocatalysts, such as alumoxanes or aluminum derivatives. For instance, European patent application EP 0 035 242 discloses a process for the polymerization of ethylene and propylene in the presence of a catalyst system comprising a cyclopentadienyl complex of a transition metal.
European patent application EP 0 129 368 discloses a catalyst system for the polymerization of olefins comprising a bis-cyclopentadienyl coordination complex with a transition metal, wherein the two cyclopentadienyl groups may be linked by a bridging group. Said bridging group is generally a divalent radical containing one or more carbon atoms (such as an ethylene group) or containing heteroatoms (such as a dimethylsilanediyl group).
Bridged metallocene compounds wherein the cyclopentadienyl residue is condensed to one or more aromatic or non aromatic ring are known in the state of the art; for example, European patent application EP 0 604 908 discloses a class of catalysts useful in the polymerization of olefins, in particular in the preparation of high molecular weight atactic polypropylene, comprising a bis-fluorenyl compound bridged by means of a one atom bridge. International application WO 95/27717, in the name of the same Applicant, discloses a class of bridged and unbridged metallocenes useful as catalytic components in the polymerization of ethylene and/or propylene, characterized by the fact that the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of 4-8 carbon atoms; examples of these metallocenes are bis(1,2-cyclotetramethyleneinden-1-yl) titaniumdichloride, dimethylsilanediyl-bis(2,3-cyclotetramethylene-inden-1-yl)-zirconium dichloride, dimethylsilanediyl-bis(2,3-octahydrofluorenyl)-zirconium dichloride and isopropyliden-(cyclopentadienyl)(2,3-cyclotetramethyleneinden-1-yl)zirconium dichloride.
The international patent application WO 98/22486, in the name of the same Applicant, describes bridged or unbridged metallocenes comprising at least a coordinating group containing a six 7 electron central radical, directly coordinating a transition metal atom, to which are associated one or more radicals containing at least one non carbon atom selected from B, N, O, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te. Said metallocenes are useful as catalyst components for the production of polyethylene and polypropylene.
The international patent application WO 98/37106 describes a polymerization catalyst system comprising a catalytic complex formed by activating a transition metal compound which comprises a group 13, 15 or 16 heterocyclic fused cyclopentadienide ligand and a metal selected from the group consisting of Group 3-9 and 10 metals; said heterocyclic fused cyclopentadienide ligand preferably contains, as endocyclic heteroatoms, one or more B, N, P, O or S atoms.
The Applicant has now unexpectedly found new metallocene compounds useful as catalyst components in the polymerization of olefins. It is an object of the present invention a class of bridged or unbridged metallocenes of formula (I):
(ZR1m)n(Cp)(A)rMLpLxe2x80x2qxe2x80x83xe2x80x83(I)
wherein (ZR1m)n is a divalent group bridging Cp and A, Z being C, Si, Ge, N or P, and the R1 groups, equal or different from each other, being H or linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl groups;
Cp is a heterocyclic cyclopentadienyl group of formula (II) or (IIxe2x80x2): 
xe2x80x83wherein one of X or Y is a single bond, the other being O, S, NR6 or PR6, R6 being hydrogen, a linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl groups, optionally containing one or more atoms belonging to groups 13-16 of the Periodic Table of the Elements (new IUPAC notation), such as B, Al, Si, Ge, N, P, O and S atoms;
R2 and R3, equal or different from each other, are selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl, C7-C20 arylalkyl, xe2x80x94OR6, xe2x80x94OCOR6, xe2x80x94SR6, PR62, wherein R6 has the meaning reported above; or R2 and R3 form together a condensed C5-C7 ring, saturated, unsaturated or aromatic, optionally containing one or more atoms belonging to groups 13-16 of the Periodic Table of the Elements (new IUPAC notation), such as B, Al, Si, Ge, N, P, O and S atoms;
the substituents R4, equal or different from each other, are selected from the group consisting of halogen, linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl, C7-20 arylalkyl, xe2x80x94OR6, xe2x80x94OCOR6, xe2x80x94SR6, xe2x80x94NR62 and xe2x80x94PR62, wherein R6 has the meaning reported above, optionally containing one or more atoms belonging to groups 13-16 of the Periodic Table of the Elements (new IUPAC notation), such as B, Al, Si, Ge, N, P, O and S atoms;
a is an integer ranging from 0 to 4;
Cp can be a partially hydrogenated derivative of the heterocyclic cyclopentadienyl group of formula (II) or (IIxe2x80x2) reported above;
A is a substituted or unsubstituted cyclopentadienyl, a group xe2x80x94NR6, R6 having the meaning reported above, or corresponds to (II) or (IIxe2x80x2), or to a partially hydrogenated derivative of (II) or (IIxe2x80x2);
M is a transition metal belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups of the Periodic Table of the Elements (IUPAC version); the substituents L, same or different from each other, are monoanionic sigma ligands selected from the group consisting of hydrogen, halogen, xe2x80x94R6, xe2x80x94OR6, xe2x80x94OCOR6, xe2x80x94OSO2CF3, xe2x80x94SR6, xe2x80x94NR62 and xe2x80x94PR62, wherein the groups R6, same or different from each other, have the meaning reported above and optionally contain Si or Ge atoms;
the substituents Lxe2x80x2, same or different from each other, are coordinating molecules, such as Lewis bases;
m is 1 or 2, and more specifically it is 1 when Z is N or P, and it is 2 when Z is C, Si or Ge;
n is an integer ranging from 0 to 4; r is 0 or 1; n is 0 when r is 0;
p and q are integers ranging from 0 to 3, p being equal to the valence of the metal M minus 2 when r=1, and minus 1 when r=0, and p+q being xe2x89xa63.
The present invention further concerns a new class of bridged ligands of formula (IV):
(ZR1m)n(CP)(A)xe2x80x83xe2x80x83(IV)
wherein Cp, A, (ZR1m)n, Z, R1 and m have the meaning reported above and n is an integer ranging from 1 to 4, particularly useful as intermediates in the preparation of the above metallocenes.
Another object of the present invention is a catalyst for the polymerization of olefins comprising said metallocenes and their use in the polymerization of olefins, particularly in the production of homo and copolymers of ethylene.
In the metallocenes of formula (I), particularly suitable as catalytic components in the polymerization of olefins, the divalent bridge (ZR1m)n is preferably selected from the group consisting of CR12, SiR12, GeR12, NR1, PR1 and (CR12)2, R1 having the meaning reported above. More preferably, said divalent bridge is Si(CH3)2, SiPh2, CH2, (CH2)2 or C(CH3)2; even more preferably, it is Si(CH3)2 or CH2.
m is 1 or 2; n ranges from 0 to 4 and, when n greater than 1, the atoms Z can be the same or different from each other, such as in the divalent bridges xe2x80x94CH2xe2x80x94Si(CH3)2xe2x80x94, xe2x80x94CH2xe2x80x94Oxe2x80x94 and xe2x80x94CH2xe2x80x94Sxe2x80x94.
According to a preferred subclass of metallocenes of the present invention, in the heterocyclic cyclopentadienyl of formula (I) or (IIxe2x80x2), R2 and R3 form together a condensed benzene ring, Cp corresponding to formula (III): 
wherein the substituents R5, equal or different from each other, are selected from the group consisting of halogen, linear or branched, saturated or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl, C7-C20 arylalkyl, xe2x80x94OR6, xe2x80x94OCOR6, xe2x80x94SR6, xe2x80x94NR62 and xe2x80x94PR62, wherein R6 has the meaning reported above; a is an integer ranging from 0 to 4; b is an integer ranging from 0 to 4; the other variables have the meaning reported above.
Cp is preferably 5,10-dihydroindeno[1,2-b]indol-10-yl, N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl or N-phenyl-5,10-dihydroindeno[1,2-b]indol-10yl, corresponding to formula (III) wherein X is NR6, R6 being hydrogen, methyl and phenyl respectively, and Y is single bond.
Furthermore, Cp can be 5,6-dihydroindeno[2,1-b]indol-6-yl, N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl, N-allyl-5,6-dihydroindeno[2,1-b]indol-6-yl or N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl, corresponding to formula (III), wherein X is a single bond and Y is NR6, R6 being hydrogen, methyl, allyl and phenyl respectively.
The group A is preferably a cyclopentadienyl residue substituted with at least a substituent selected from the group consisting of H, linear or branched, saturated or unsaturated C1-C10 alkyl, C6-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl and C7-C20 arylalkyl radicals. preferably, A is cyclopentadienyl, 4-butyl-cyclopentadienyl, 4-adamantyl-cyclopentadienyl, indenyl, tetrahydroindenyl or fluorenyl. According to a preferred embodiment of the invention, A is equal to Cp.
r can be 0 or 1; when r=0, then n=0.
M is preferably Ti, Zr or Hf, and more preferably Zr.
The substituents L are preferably halogen atoms or R6 groups, R6 being defined as reported above; more preferably the substituents L are Cl or CH3.
p and q are integers ranging from 0 to 3, p being equal to the valence of the metal M minus 2 when r=1, and minus 1 when r=0, and p+q being xe2x89xa63;
An advantageous class of the metallocenes according to the present invention correspond to formula (1), wherein n=0 and r=1, i.e. Cp and A groups are not linked to each other by a bridging divalent residue. Non limitative examples of said class are:
bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)titanium dichloride;
bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)zirconium dichloride;
bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)hafnium dichloride;
bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)titanium dichloride;
bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)zirconium dichloride;
bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)hafnium dichloride;
bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)titanium dichloride;
bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)hafnium dichloride;
bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)titanium dichloride;
bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)hafnium dichloride;
bis(N-methyl-1,8-dihydroindeno [2,1-b]pyrrol-8-yl)zirconium dichloride;
bis(N-methyl-2-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)zirconium dichloride;
bis(N-phenyl-2-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)zirconium dichloride;
(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(fluorenyl) zirconium dichloride;
(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(octahydrofluorenyl) zirconium dichloride;
(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(cyclopentadienyl) zirconium dichloride;
(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(3-tbutyl-cyclopentadienyl)zirconium dichloride;
(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(3-adamantylcyclopentadienyl) zirconium dichloride;
(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(fluorenyl) zirconium dichloride;
(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(fluorenyl) zirconium dichloride;
(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(octahydrofluorenyl)zirconium dichloride;
(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(cyclopentadienyl) zirconium dichloride;
(N-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)(cyclopentadienyl) zirconium dichloride;
(N-methyl-5,8-dihydroindeno[2,1-b]pyrrol-8-yl)(fluorenyl) zirconium dichloride;
(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(fluorenyl) zirconium dichloride;
(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(2,7-di-t-butyl-fluorenyl) zirconium dichloride;
(N-phenyl-5,6-dihydroindeno[2,1-b)indol-6-yl)(octahydrofluorenyl)zirconium dichloride;
(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)(cyclopentadienyl) zirconium dichloride;
and the corresponding titanium, zirconium or hafnium dimethyl derivatives.
Another advantageous class of metallocenes according to the present invention corresponds to formula (I) wherein n is different from 0, r is equal to 1 and the groups Cp and A, preferably the same, corresponds to cyclopentadienyl heterocyclic derivatives of formula (II) or (IIxe2x80x2); preferably, the divalent group (ZR1m)n is Si(CH3)2, SiPh2, CH2, (CH2)2 or C(CH3)2; even more preferably, it is Si(CH3)2 or CH2.
Non limitative examples of said metallocenes are:
dimethylsilanediyl-bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl) titanium dichloride;
dimethylsilanediyl-bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl) zirconium dichloride;
dimethylsilanediyl-bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl) hafnium dichloride;
ethylen-bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl) zirconium dichloride;
isopropyliden-bis(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl) zirconium dichloride;
dimethylsilanediyl-bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl) zirconium dichloride;
ethylen-bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl) zirconium dichloride;
isopropyliden-bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl) zirconium dichloride;
dimethylsilanediyl-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)titanium dichloride;
dimethylsilanediyl-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
dimethylsilanediyl-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)hafnium dichloride;
dimethylsilanediyl-bis(N-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)zirconium dichloride;
methylen-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
metlylen-bis(N-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)zirconium dichloride;
ethylen-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
isopropyliden-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
isopropyliden-bis(N-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)zirconium dichloride;
dimethylsilanediyl-bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
methylen-bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
ethylen-bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
isopropyliden-bis(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)zirconium dichloride;
dimethylsilanediyl-(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(cyclopentadienyl)zirconium dichloride;
dimethylsilanediyl-(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(cyclopentadienyl) zirconium dichloride;
ethylen(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(cyclopentadienyl)zirconium dichloride;
ethylen(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(cyclopentadienyl)zirconium dichloride;
isopropyliden(N-methyl-5,10-dihydroindeno(1,2-b]indol-10-yl)(cyclopentadienyl)zirconium dichloride;
isopropyliden-bis(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)(cyclopentadienyl) zirconium dichloride;
and the corresponding zirconium dimethyl derivatives.
A particularly preferred metallocene is methylen-bis(N-methyl-5,6-dihydroindeno[2,1-b]indol6-yl)zirconium dichloride or dimethyl.
Another object of the present invention is a class of ligands of formula (IV):
(ZR1m)n(CP)(A)xe2x80x83xe2x80x83(IV)
wherein the variables Cp, A, (ZR1m)n, Z, R1 and m have the meanings reported above and n is an integer ranging from 1 to 4. Said ligands are useful as intermediates in the preparation of the metallocenes according to the present invention.
In the above bridged ligands, the divalent bridge (ZR1m)n is preferably selected from the group consisting of Si(CH3)2, SiPh2, CH2, (CH2)2 and C(CH3)2.
Cp is a heterocyclic cyclopentadienyl group of formula (II) or (IIxe2x80x2), reported above, and preferably corresponds to formula (III), reported above; even more preferably, Cp is selected from the group consisting of N-methyl-5,10-dihydroindeno[1,2-b]indolyl, N-phenyl-5,10-dihydroindeno[1,2-b]indolyl, N-allyl-5,10-dihydroindeno[1,2-b]indolyl, N-methyl-5,6-dihydroindeno[2,1-b]indolyl, N-phenyl-5,6-dihydroindeno[2,1-b]indolyl, N-allyl-5,6-dihydroindeno[2,1-b]indolyl and N-methyl-1,8-dihydroindeno[2,1-b]pyrrolyl.
The group A can be a cyclopentadienyl derivative or a group of formula (II) or (IIxe2x80x2), and preferably of formula (III); even more preferably, A is equal to Cp.
Non limitative examples of the bridged ligands according to the present invention are:
10-[1,1-dimethyl-1-(5,10-dihydroindeno[1,2-b]indol-10-yl)silyl]-5,10-dihydroindeno[1,2-b]indole;
10-[(5,10-dihydroindeno[1,2-b]indol-10-yl)methyl]-5,10-dihydroindeno[1,2-b]indole;
10-[2-(5,10-dihydroindeno[1,2-b]indol-10-yl)ethyl]-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(5,10-dihydroindeno[1,2-b]indol-10-yl)ethyl]-5,10-dihydroindeno[1,2-b]indole;
10-[1,1-dimethyl-1-(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)silyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)methyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[2-(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)ethyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(N-methyl-5,10-dihydroindeno[1,2-b]indol-10-yl)ethyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[1,1-dimethyl-1-(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)silyl]-N-phenyl-5,10-dihydroindeno[1,2-b]indole;
10-[(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)methyl]-N-phenyl-5,10-dihydroindeno[1,2-b]indole;
10-[2-(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)ethyl]-N-phenyl-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(N-phenyl-5,10-dihydroindeno[1,2-b]indol-10-yl)ethyl]-N-phenyl-5,10-dihydroindeno[1,2-b]indole;
6-[1,1-dimethyl-1-(5,6-dihydroindeno[2,1-b]indol-6-yl)silyl]-5,6-dihydroindeno[2,1-b]indole;
6-[(5,6-dihydroindeno[2,1-b]indol-6-yl)methyl]-5,6-dihydroindeno[2,1-b]indole;
6-[2-(5,6-dihydroindeno[2,1-b]indol-6-yl)ethyl]-5,6-dihydroindeno[2,1-b]indole;
6-[1-methyl-1-(5,6-dihydroindeno[2,1-b]indol-6-yl)ethyl]-5,6-dihydroindeno[2,1-b]indole;
6-[1,1-dimethyl-1-(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)silyl]-N-methyl-5,6-dihydroindeno[1,2-b]indole;
8-[1,1-dimethyl-1-(N-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)silyl]-N-methyl-1,8-dihydroindeno[1,2-b]pyrrole;
6-[(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)methyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole;
8-[(N-methyl-1,8-dihydroindeno[2,1-b]pyrrol-8-yl)methyl]-N-methyl-1,8-dihydroindeno[2,1-b]pyrrole; 6-[2-(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)ethyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole;
6-[1-methyl-1-(N-methyl-5,6-dihydroindeno[2,1-b]indol-6-yl)ethyl]-N-methyl-5,6-dihydroindeno[2,1-]indole;
6-[1,1-dimethyl-1-(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)silyl]-N-phenyl-5,6-dihydroindeno[2,1-b]indole;
6-[(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)methyl]-N-phenyl-5,6-dihydroindeno[2,1-b]indole;
6-[2-(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)ethyl]-N-phenyl-5,6-dihydroindeno[2,1-b]indole;
6-[1-methyl-1-(N-phenyl-5,6-dihydroindeno[2,1-b]indol-6-yl)ethyl]-N-phenyl-5,6-dihydroindeno[2,1-b]indole;
10-[1,1-dimethyl-1-(cyclopentadienyl)silyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[(cyclopentadienyl)methyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[2-(cyclopentadienyl)ethyl]N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[2-(cyclopentadienyl)ethyl]N-phenyl-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(cyclopentadienyl)ethyl]N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(3-tbutyl-cyclopentadienyl)ethyl]N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(3-adamantyl-cyclopentadienyl)ethyl]N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[1,1-methyl-1-(fluorenyl)silyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[(fluorenyl)methyl]-N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[2-(fluorenyl)ethyl]N-methyl-5,10-dihydroindeno[1,2-b]indole;
10-[1-methyl-1-(fluorenyl)ethyl]N-methyl-5,10-dihydroindeno[1,2-b]indole;
6-[1,1-dimethyl-1-(cyclopentadienyl)silyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole; 6-[(cyclopentadienyl)methyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole;
6-[1,1-dimethyl-1-(fluorenyl)silyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole;
6-[1,1-dimethyl-1-(2,7-di-butyl-fluorenyl)silyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole;
6-[1-methyl-1-(fluorenyl)ethyl]N-methyl-5,6-dihydroindeno[2,1-b]indole.
A particularly preferred bridged ligand is 6-[(N-methyl-5,6-dihydroindeno[2,1-]indol-6-yl)methyl]-N-methyl-5,6-dihydroindeno[2,1-b]indole.
The ligands of the invention can be prepared according to general procedures known in the state of the art, starting from commercially obtainable products or from derivatives which can be prepared by known methods. More specifically, when the group A is equal to the group Cp, the above ligands can be prepared by first reacting a compound of formula (V) or (Vxe2x80x2): 
wherein X, Y, R2, R3, R4 and a have the meanings reported above, with a compound able to form a delocalized anion on the cyclopentadienyl ring, and thereafter with a compound of formula (ZR1m)nW2, wherein Z, R1, m and n are defined as above and the substituents W, same or different from each other, are halogen atoms or tosylate groups. Non limitative examples of compounds of formula (ZR1m)nW2 are dimethyldichlorosilane, diphenyldichlorosilane, dimethyldichlorogermanium, 2,2-dichloropropane and 1,2-dibromo-ethane.
The synthesis of the above bridged ligands is preferably carried out by adding a solution of an organic lithium compound in an apolar solvent to a solution of the compound (V) or (Vxe2x80x2) in an aprotic polar solvent. The thus obtained solution containing the compound (V) or (Vxe2x80x2) in the anionic form is then added to a solution of the compound of formula (ZRm)nW2 in an aprotic polar solvent. The bridged ligand can be finally separated by general procedures known in the state of the art.
Not limitative examples of aprotic polar solvents which can be used in the above process are tetrahydrofurane, dimethoxyethane, diethylether, toluene and dichloromethane. Not limitative examples of apolar solvents suitable for the above process are pentane, hexane and benzene.
During the whole process, the temperature is preferably kept between xe2x88x92180xc2x0 C. and 80xc2x0 C., and more preferably between xe2x88x9220xc2x0 C. and 40xc2x0 C.
The preparation of the bridged ligands of formula (IV), when the group A is different from the group Cp, can be carried out by reacting an anionic salt of a compound of formula A) or (Vxe2x80x2) with a substituted A group.
The metallocene compounds of formula (I), when n is different from 0 and r is 1, can be prepared by first reacting the bridged ligands (ZR1m)n(Cp)(A),prepared as described above, with a compound able to form a delocalized anion on the cyclopentadienyl rings, and thereafter with a compound of formula ML4, wherein M and the substituents L are defined as above. Non limitative examples of compounds of formula ML4 are titanium tetrachloride, zirconium tetrachloride and hafnium tetrachloride.
More specifically, said bridged ligands are dissolved in an aprotic polar solvent and to the obtained solution is added a solution of an organic lithium compound in an apolar solvent. The thus obtained anionic form is separated, dissolved in an aprotic polar solvent and thereafter added to a suspension of the compound ML4 in an aprotic polar solvent. At the end of the reaction, the solid product obtained is separated from the reaction mixture by techniques commonly used in the state of the art. Not limitative examples of aprotic polar solvents suitable for the above reported processes are tetrahydrofurane, dimethoxyethane, diethylether, toluene and dichloromethane. Not limitative examples of apolar solvents suitable for the above process are pentane, hexane and benzene.
During the whole process, the temperature is preferably kept between xe2x88x92180xc2x0 C. and 80xc2x0 C., and more preferably between xe2x88x9220xc2x0 C. and 40xc2x0 C.
The metallocene compounds of formula (I), wherein n=0 and r=1, can be prepared by reacting the anions of the ligands Cp and A with a tetrahalide of the metal M (i.e. ML4), M and L having the meanings reported above, said reaction being carried out in a suitable solvent.
Metallocene compounds of formula (I) according to the present invention, wherein Cp and A are partially hydrogenated, can be suitably prepared by hydrogenation of the corresponding metallocene compounds in which Cp and optionally A corresponds to formula (I) or (IIxe2x80x2). The hydrogenation reaction is carried out in a suitable solvent such as CH2Cl2, in the presence of a suitable hydrogenation catalyst such as PtO2, and hydrogen. Hydrogen pressure is preferably comprised between 1 and 100 bar, and the temperature is preferably comprised between xe2x88x9250 and 50xc2x0 C.
When at least one L substituent in the metallocene compound of formula (I) is different from halogen, it is necessary to substitute at least one substituent L in the obtained metallocene with at least another substituent different from halogen. Such a substitution reaction is carried out by methods known in the state of the art. For example, when the substituents L are alkyl groups, the metallocenes can be reacted with alkylmagnesium halides (Grignard reagents) or with lithiumalkyl compounds.
A further object of the present invention is a catalyst for the polymerization of olefins comprising the reaction product between:
(1) a metallocene compound of formula (I), optionally as a reaction product with an organo-aluminum compound of formula AlR73 or Al2R76, in which the substituents R7, same or different from each other, have the meaning of R4 or are halogen, and;
(2) an alumoxane, optionally in admixture with an organo-aluminum compound of formula AlR3 or Al2R7, the substituents R7 having the meanings reported above, or one or more compounds capable of forming an alkyl metallocene cation.
The alumoxane used as component (2) can be obtained by reacting water with the organo-aluminum compound of formula AlR73 or Al2R76, with the condition that at least one R7 is not halogen. In this case, the molar ratios of Al/water in the reaction is comprised between 1:1 and 100:1.
The molar ratio between aluminum and the metal of the metallocene is comprised between about 10:1 and about 5000:1, and preferably between about 100:1 and about 4000:1.
The alumoxane used in the catalyst according to the invention is believed to be a linear, branched or cyclic compound, containing at least one group of the type: 
wherein the substituents R8, same or different from each other, have the meaning of R4 or are a group xe2x80x94Oxe2x80x94Al(R8)2.
Examples of alumoxanes suitable for the use according to the present invention are methylalumoxane (MAO), isobutylalumoxane (TIBAO) and tris(2,4,4-trimethyl-pentyl)aluminoxane (TOAO).
Mixtures of different alumoxanes are suitable as well. Not limitative examples of aluminum compounds of formula AlR73 or Al2R76 are:
Al(Me)3, Al(Et)3, Al(Et)2, Al(iBu)3, AlH(iBu)2, Al(iHex)3, Al(C6H5)3, Al(CH2C6H5)3, Al(Ch2CMe3)3, Al(CH2SiMe3)3, Al(Me)2iBu, Al(Me)2Et, AlMe(Et)2, AlMe(iBu)2Al(Me)2iBu, Al(Me)2Cl, Al(Et)2Cl , AlEtCl2, Al2(Et)3Cl3, wherein Me=methyl, Et=ethyl, iBu=isobutyl, iHex=isohexyl.
Among the above mentioned aluminum compounds, tris-(2,4,4-trimethyl-pentyl)aluminum (TIOA), trimethylaluminum (TMA) and triisobutylaluminum (TIBA) are preferred.
Not limitative examples of compounds able to form a metallocene alkyl cation are compounds of formula J+Kxe2x88x92, wherein J+ is a Bronsted acid, able to give a proton and to react irreversibly with a substituent of the compound of formula (I) and Kxe2x88x92 is a compatible anion, which does not coordinate, which is able to stabilize the active catalytic species which originates from the reaction of the two compounds and which is sufficiently labile to be able to be removed from an olefinic substrate. Preferably, the anion Kxe2x88x92 comprises one or more boron atoms. More preferably, the anion Kxe2x88x92 is an anion of the formula BAr(xe2x88x92)4, wherein substituents Ar, same or different from each other, are aryl radicals such as phenyl, pentafluorophenyl, bis-(trifluoromethyl)-phenyl. Particularly preferred is the tetrakis-pentafluorophenyl-borate. Furthermore, compounds of formula BAr3 can be suitably used.
The catalysts of the present invention can also be used on an inert support, by depositing the metallocene component (1), or the reaction product of the metallocene component(1) with component (2), or the component (2) and successively the metallocene component (1), on the inert support, such as silica, alumina, styrene-divinylbenzene copolymers or polyethylene.
The solid compound so obtained, in combination with further addition of the alkyl aluminum compound as such or prereacted with water, is usefully employed in gas phase polymerization.
The catalysts of the present invention can be advantageously used in homo or copolymerization of olefins. Therefore, a further object of the invention is a process for the polymerization of olefins, comprising the polymerization reaction of at least one olefinic monomer in the presence of the above described catalyst.
When is used a metallocene compound of formula (I), wherein n=1 and the group A is a non-substituted cyclopentadienyl group, the obtained xcex1-olefin homopolymers have a predominantly syndiotactic structure. Alternatively, when is used a metallocene of formula (1), wherein n=1 and the group A is a substituted cyclopentadienyl group, the obtained xcex1-olefin homopolymers have an isotactic structure.
The catalysts of the present invention can be used in the homo-polymerization reaction of olefins, preferably of ethylene for the preparation of HDPE, or of xcex1-olefins, such as propylene and 1-butene. In ethylene polymerization, the metallocenes of the invention show excellent activities even when used in very low Zr/Al ratios.
Another interesting use of the catalysts according to the present invention is in the copolymerization of ethylene with higher olefins. In particular, the catalysts of the invention can be used for the preparation of LLDPE. The LLDPE copolymers which are obtained have a density higher than 0.9 g/ml and very low xylene soluble percentages.
Suitable olefins to be used as comonomers comprise xcex1-olefins of the formula CH2xe2x95x90CHR, wherein R is an alkyl radical having from 1 to 10 carbon atoms, and cycloolefis. Examples of these olefins are propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-esadecene, 1-octadecene, 1-eicosene, allylcyclohexene, cyclopentene, cyclohexene, norbornene and 4,6-dimethyl-1-heptene.
The copolymers may also contain small proportions of units deriving from polyenes, in particular from straight or cyclic, conjugated or non conjugated dienes, such as 1,4-hexadiene, isoprene, 1,3-butadiene, 1,5-hexadiene and 1,6-heptadiene. The units deriving from xcex1-olefins of formula CH2xe2x95x90CHR, from cycloolefins and/or from polyenes are present in the copolymers preferably in amounts ranging from 1 % to 20% by mole.
The catalyst of the invention can also be used for the preparation of elastomeric copolymers of ethylene with xcex1-olefins of formula CH2xe2x95x90CHR, R having the meaning reported above, optionally containing small quantities of units deriving from polyenes.
The saturated elastomeric copolymers can contain ethylene units and xcex1-olefins and/or non conjugated diolefins able to cylopolymerize. The unsaturated elastomeric copolymers can contain, together with the units deriving from the polymerization of ethylene and xcex1-olefins, also small proportions of unsaturated units deriving from the copolymerization of one or more polyenes. The content of unsaturated units is preferably comprised between 0.1 and 5% by weight.
Non limitative examples of suitable xcex1-olefins comprise propylene, 1-butene and 4-methyl-1-pentene. Suitable non conjugated diolefins able to cyclopolymerize comprise 1,5-hexadiene, 1,6-heptadiene and 2-methyl-1,5-hexadiene.
Non Limitative Examples of Suitable Polyenes are:
(i) polyenes able to give unsaturated units, such as:
linear, non-conjugated dienes, such as 1,4-hexadiene trans, 1,4-hexadiene cis, 6-methyl-1,5-heptadiene, 3,7-dimethyl-1,6-octadiene and 11-methyl-1,10-dodecadiene; monocyclic diolefins, such as cis-1,5-cyclooctadiene and 5-methyl-1,5-cyclooctadiene;
bicyclic diolefins, such as 4,5,8,9-tetrahydroindene and 6 and 7-methyl-4,5,8,9-tetrahydroindene;
alkenyl or alklyliden norbornenes, such as 5-ethlyliden-2-norbornene, 5-isopropyliden-2-norbornene and exo-5-isopropenyl-2-norbornene;
polycyclic diolefins, such as dicyclopentadiene, tricyclo-[6.2.1.02.7]4,9-undecadiene and the 4-methyl derivative thereof;
(ii) non-conjugated diolefins able to cyclopolymerize, such as 1.5-hexadiene, 1,6-heptadiene and 2-methyl-1,5-hexadiene;
(iii) conjugated dienes, such as butadiene and isoprene.
Another object of the present invention is a process for the polymerization of propylene carried out in the presence of the above described catalyst.
A further interesting use of the catalysts according to the present invention is for the preparation of cycloolefin polymers. Monocyclic and polycyclic olefin monomers can be either homopolymerized or copolymerized, also with linear olefin monomers.
Polymerization processes according to the present invention can be carried out in gaseous phase or in liquid phase, optionally in the presence of an inert hydrocarbon solvent either aromatic (such as toluene), or aliphatic (such as propane, hexane, heptane, isobutane and cyclohexane).
The polymerization temperature is preferably ranging from about 0xc2x0 C. to about 250xc2x0 C. In particular, in the processes for the preparation of HDPE and LLDPE, it is preferably comprised between 20xc2x0 C. and 150xc2x0 C. and, more preferably between 40xc2x0 C. and 90xc2x0 C., whereas for the preparation of the elastomeric copolymers it is preferably comprised between 0xc2x0 C. and 200xc2x0 C. and, more preferably between 20xc2x0 C. and 100xc2x0 C.
The molecular weight of the polymers can be varied by changing the polymerization temperature, the type or the concentration of the catalyst components or by using molecular weight regulators, such as hydrogen. The fact that the catalysts of the invention are sensitive to hydrogen as a molecular weight regulator is unexpected in view of the fact that, if the polymerization is carried out in the presence of a metallocene compound according to the cited EP 0 604 908, the hydrogen has no effect on the molecular weight of the obtained polymers, even if used in relevant amounts.
The molecular weight distribution can be varied by using mixtures of different metallocenes or by carrying out the polymerization in various steps differing in the polymerization temperature and/or in the concentration of the molecular weight regulators.
The polymerization yield depends on the purity of metallocenes in the catalyst; the metallocene according to the present invention may be used as such or may be previously subjected to purification treatments.
Particularly interesting results are obtained when the components of the catalyst are contacted among them before the polymerization. The contact time is generally comprised between 1 and 60 minutes, preferably between 5 and 20 minutes. The pre-contact concentrations for the metallocene component (1) are comprised between 10xe2x88x922 and 10xe2x88x928 mol/l, whereas for the component (2) they are comprised between 10 and 10xe2x88x923 mol/l. The precontact is generally carried out in the presence of a hydrocarbon solvent and, optionally, of small amounts of monomer.